How do I see the word count for each chapter?

In Word

Word counts two things: the whole document, or whatever you have selected. So the trick is selecting exactly one chapter. On Windows it takes a right-click when your chapter titles use a Heading style: open the Navigation Pane from the View tab and right-click a chapter's heading to choose Select Heading and Content. The status bar at the foot of the window then reads something like 3,412 of 96,870 words, and the first number is the chapter.

On a Mac, or wherever that item is missing, click at the start of the chapter and Shift-click at its end. It works. On a long book the scrolling is slow, though, and the whole routine has to be repeated for every chapter you want to measure, every time that chapter changes.

Writers who want every chapter at once usually reach for a macro that walks the headings and prints a table of counts, which is reliable if your headings are consistent and a small maintenance job if they are not.

In Google Docs

Select the chapter and press Ctrl+Shift+C (⌘+Shift+C on a Mac). The Word count box then shows the selection against the document's total. Tick Display word count while typing and a small counter stays in the corner, following whatever you select.

If you have split the book into tabs, one chapter to a tab, the same command counts only the tab you are in. That is the nearest Docs comes to a per-chapter count without an add-on, though it gives up the whole-book total in exchange. Several add-ons in the Workspace Marketplace list a count for every heading. They are worth trying if you check often.

In Tabularia

Every row of the Outline carries its own count, from a Book at the top down to the smallest heading inside a scene. Nothing needs selecting. The count sits on the row's second line, so switching the Outline to compact rows hides it until you switch back.

The counts in the document header follow the Working Scope, so setting it to Current Chapter makes the header count that chapter, and Current Scene counts the scene. Pin a filtered Outline — say, every scene labeled with one character's point of view — and the header counts just those passages, scattered as they are through the book. The header's other counts and its display options are covered in Goals and statistics.

One limit: on a phone the header's counts are withheld to save room. They come back on a tablet or a desktop.